coondoggie writes: "How do you keep a robot from getting tired? Sounds like the set-up line for a joke, but the scientists at Defense Advanced Research Projects Agency have put out a call for technology that significantly bolsters robot energy efficiency while increasing its range and endurance. Within what it calls the Maximum Mobility and Manipulation (M3) program DARPA said it wants to develop and demonstrate high efficiency "actuation technology" that will let robots similar to the DARPA Robotics Challenge have 20 times longer endurance."